Industrial control systems are now used in almost every industrial area, such as oil & gas, chemical, pharmaceutical, paper, mining and metal. In order to improve reliability of the industrial control system, a redundant device is used for devices of the industrial control system, such as input/output modules (I/O modules), so that the fault of one or more of the devices in the industrial control system will not affect the operation of the whole industrial control system. Normally, when there is a fault, the active device of the industrial control system (i.e. the device which is performing the data transmitting with its corresponding field device), can detect whether it is a fault about the links connected between the active device of the industrial control system and its field device or it is a fault occurred in the active device itself. Generally, if a fault in the link, e.g. link break and short circuit, is detected, the detected fault is usually considered as a fault in the immediate link connected with the field device which is usually shared by the active device and its redundant device, thus current industrial control systems do not execute switchover between the active device and its redundant device under such situation, since the fault of the link shared by the active device and its redundant device will cause endless switchover.
However, the detected faults in the link connected between the active device of the industrial control system and the field device comprise not only the faults in the link shared by the active device and its redundant device, but also the faults of the link not shared by the active device and its redundant device. The prior art does not give a thought on this and thus the efficiency of fixing the fault is lowered.
Therefore, there is a need to provide a technology to overcome the above disadvantages.